Hi

my apologies, if i'm posting at the wrong place.  my first post !!

i'm looking to buy Antminer from (www.jopendi.com) and wanted to check if others might have bought from them before.  The website was set-up a few months ago and i wanted to make sure its legitimate.  

I have offered to meet them in their office and purchase the items with cash, but they have turned me down.

Hope to hear from your experiences with Jopendi.

thank you

All mined bitcoins are donated to the NastyFans organization and distributed to it's members on a weekly basis.  You can become a member and receive a share of future Bitcoin distributions by purchasing seats at NastyFans.org.

Solar Equipment:
29x SunPower E20 327W AC Modules w/ Integrated Microinverter (link)

Bitcoin Hardware:
2x Bitmain S9 (link)
1x Bitmain R4 (link)

Solar Statistics:
Coming Soon!

Mining Hashrate:

(click to enlarge)

Ease of setup is essential, but I also want to look at overall cost, reliability and fault tolerance. A controller per miner ensures no one box can affect the operation of another, but also has the highest cost.  A single controller for a fleet of miners is the cheapest and easiest to configure, but also provides a nice single point of failure. A single controller with chained boxes means if you pull any one cable, every miner downstream is also disconnected. Using a single controller with a tree structure of connected boxes reduces (but does not remove) this problem, and still leaves you with the controller as a single point of control but also failure.

I like the idea of the single controller being something generic and replaceable like the Pi. If your Avalon6 controller craps out, you don't have to email warranty claims and wait a week for them to deny your claim. Just go to any of a thousand online vendors and pick up a new one for like $20 - or if you're that worried about it, already have one standing by just in case. Avalon sending a Pi with the SD card already imaged is really nice.

The easiest busses for consumers to work with, as far as setting up a tree of connections using readily available hardware is concerned, would be Ethernet and USB. I'm in favor of USB from the standpoint of ease of interface (you can get $2 microcontrollers with full USB capability) and availability of software to build upon, but Ethernet does make distribution easier what with better cabling and generally more reliable hardware. The problem with ethernet comes from controlling it - either the miners have to be on a private network and a dual-NIC controller is present, or the miners exist on the same network which adds work to detection and preventing control overlaps.

Oh yeah, I was ecstatic when the S5s started showing up with DHCP enabled by default. Very glad to see that change. My entire hosting is run off static leases on the DHCP server, makes everything super easy.

Don't forget, all transactions need to be accompanied with a signed message to verify.

Don't forget, all transactions need to be accompanied with a signed message to verify.

good idea - the only reason the fans were on the end was to address space requirements.


and you can get your dremel took out and cut the end off also.

The problem isn't that there isn't a market. The problem is that it's a harder market. Shipping a hundred machines on a pallet to one technically-competent person is a lot easier than shipping out a hundred machines to a hundred idiots who then need support. So they're willing to take a slight hit (in Bitmain's case, it's what, 1% off the purchase price?) to sell to a few giants who won't ask a lot of questions rather than sell to a thousand idiots with a dozen questions each if you get the same amount of money from either group. Bitmain wants to maximise profits, and if you can get the same revenue while unloading 90% of your support staff salary your profits just went up.

If I knew that I was guaranteed to sell 1000 units, it'd be worth my time to R&D and manufacture a small miner. It's not that the dev and manufacturing costs aren't enough to recoup it. The logistics of mass shipping and customer support (which Bitmain has sucked at for years now, think how much worse it'd be with twice as many customers) is what makes it annoying. Actually, what I want to build I can pretty much guarantee will sell at least 1000 units; the only thing stopping me is access to chips.

most likely it earning would stay over power cost for 4 months  then the ½ ing comes most likely that puts your earnings under power cost.


So if you get one cheap and are willing to sell it in late June you may earn a profit.

Well, mining is self-regulating. The halving is going to hurt a lot, but it's not like bitcoin's going to disappear. What becomes unprofitable to run will no longer be run, coin prices will go up, fees will go up, and the system will keep on running. If anything has a chance to be profitable, it'll be the most efficient chip available at the time. That's dependent a lot on initial cost, but the market is adjustable as well - if BitFury can't sell enough of them at whatever price, they'll either use 'em themselves or lower the price. There are way too many variables to make any sort of accurate prediction, but the fact that pretty soon 99% of the world won't be able to turn a buck with 0.3J/GH gear helps the assumed viability of 0.1J/GH gear.

What's the numbers for a 48-chip refit giving you 4TH 240W wall down to 2.6TH 200W wall for, say, $600 all in? That could be possible with ASICs at about $8, which is really about the most I'd want to pay.

I want buy used S7, acceptable price is 900$ per 1 unit

I am ready pay first then you will ship miner for me, but I need verify that miner in good condition before I sent money.

wow man, this project is awesome.  Would be nice to know (roughly) the cost to install panels like that for a normal consumer (not what he paid for).  I have neighbors who have some pannels, but somehow I don't think it will ROI in this lifetime, my electric is under 0.05cents CAD, and when its really cold its more expensive though.  normal rates are below 9cents CAD.

So now I guess it's a race, Gekkoscience et al versus miner.bz?

So replacing the control board also. That's a bit more logical.

I don't quite understand stealing a publicity render for a machine when, if you're modifying an S5, you could have taken a photo of an S5 and sketched new boards on to it for something a little more accurate and a little less shady.

Say, that sounds an awful lot like something I'm working on.

According to Novak's best guess, the problem was that USB2 was limited to 1000 packets per second regardless of size. Not sure if USB3 has the same problem.

I think this is at least the third time you've been told this, but with your 49-port hub the limitation won't be power. The limitation will be USB's packet throughput limit, which will cap your total hashrate to about 300GH per connection (which is to say, per hub) due to not being able to keep them provided with work.

Say, that sounds an awful lot like something I'm working on.